Tips and Tricks for Cation-Exchange Chromatography for the iTRAQ® Protocol

For research use only. Not for use in diagnostic procedures.

Answer

Below is the cation exchange setup for the manual injection procedure when using the iTRAQ® reagent:
A 22-gauge syringe with a 2-inch needle is recommended in the iTRAQ protocol, but the 2-inch needle is no longer available. So instead, an 18-gauge syringe with a 2-inch needle is recommended.

Here are some tricks and tips when setting up for manual injection of the cation-exchange column:

• Using syringes with Luer-lock connections may help prevent leakage.
• A 1-inch needle may not sit fully in the needle port adapter, so the 2-inch needle is recommended.
• If something other than a blunt-end needle was used at any point, the tubing inside the needle point adapter may be torn. 
• The tubing inside needle point adapter might have been twisted or stretched (when doing what?). 
• The user might exert too much pressure on the plunger of the syringe. 
• The 18-gauge needle is a larger inner diameter than the 22-gauge.
• Change ferrules both in and out and change outlet tubing. These may be crushed and causing back pressure (when do they need to be changed?).